In modern aircraft, sensors provide comprehensive information concerning the status of the aircraft, and such information is displayed to the crew via a large number of individual electromechanical displays. Each such display typically comprises means for indicating a series of decimal digits representing a parameter such as altitude, and/or an analog type display in which the parameter is indicated by the position of a pointer on a circular dial. In general, there are two types of problems associated with conventional electromechanical displays. The first problem relates to the fact that such displays are proliferating in the cockpits of modern jet aircraft, resulting in high costs for engineering, manufacturing, training, company documentation and operator logistics. As flight control systems become more complex, display formats and arrangements are growing proportionately in complexity, thereby complicating wiring, cooling, crew operational procedures, and customer maintenance.
A second problem with conventional electromechanical displays is that such displays, as presently formatted, require the crew to read the displays one at a time using foveal rather than peripheral vision. Foveal vision is vision using the small central area of the retina that has the highest visual acuity. The need to scan a large and increasing number of electromechanical displays using foveal vision requires the crew to apply integrative processing from the individual displays and mentally construct the present aircraft configuration or flight status. The consequence of this limitation of conventional electromechanical displays is apparent in the large difference in performance between a human operator under Visual Flight Rules (VFR) conditions with real world cues, and one under Instrument Flight Rules (IFR) conditions with only instrument information from electromechanical displays. In good VFR conditions, the average pilot is capable of landing an aircraft with a high degree of accuracy, and with relatively little effort. Under IFR conditions, with only instruments as a guide, landing can be a difficult task. Crop dusters and acrobatic flying teams do not fly on instruments.